The invention relates to remote center compliance units and, more particularly, comprises an improved compliance element for such units.
Remote center compliance units provide a compliant interface between a machine and a part being assembled or otherwise manipulated. Compliance units typically hold an assembly part or tool and establish a center of compliance that usually lies at some distance beyond the unit itself, usually at the point where the part or tool held by the unit contacts the other part being assembled or worked upon. Lateral forces applied at this remote center appear as pure lateral movements in the compliance element; similarly, moments applied about the center of compliance appear as rotations of the compliance element about this center. Accordingly, small offsets or misorientations of the parts being manipulated or assembled are accomodated by the compliance unit and the assembly or other operation can proceed smoothly and without generating large counterforces that could otherwise result from misalignment.
Units of this kind are described in more detail in U.S. Pat. No. 4,155,169 entilted, "Compliant Assembly System Device", and issued May 22, 1979, to Samuel H. Drake and Sergio N. Simunovic and U.S. Pat. No. 4,098,001 entitled, "Remote Center Compliance System", issued July 4, 1978 to Paul C. Watson. These patents describe remote center compliance units utilizing a pair of platforms interconnected by a number of compliance elements. A remote center compliance unit utilizing three platforms interconnected in pairs by compliance elements is described in report number T-657, "Using Compliance in Lieu of Sensory Feedback for Automatic Assembly", by Samuel H. Drake, issued September 1977 by the C. S. Draper Laboratory, Inc. The compliance elements of the present invention are usable in both the two-platform and three-platform versions of compliance units described in these references, as well as in other kinds of compliance units as well.